package com.cn.wanxi.util;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.List;

public class UploadTool {
    private static final long serialVersionUID = 1L;

    // 上传文件存储目录
    private static final String UPLOAD_DIRECTORY = "upload";

    // 上传配置
    private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3;  // 3MB
    private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
    private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB

    public static String upload(HttpServletRequest req, HttpServletResponse resp) {
        // 检测是否为多媒体上传
        if (!ServletFileUpload.isMultipartContent(req)) {
            // 如果不是则停止
            PrintWriter writer = null;
            try {
                writer = resp.getWriter();
            } catch (IOException e) {
                e.printStackTrace();
            }
            writer.println("Error: 表单必须包含 enctype=multipart/form-data");
            writer.flush();
            return "";
        }

        // 配置上传参数
        DiskFileItemFactory factory = new DiskFileItemFactory();
        // 设置内存临界值 - 超过后将产生临时文件并存储于临时目录中
//        factory.setSizeThreshold(MEMORY_THRESHOLD);
        // 设置临时存储目录
//        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));

//        解析将前端传递过来的数据进行解析
        ServletFileUpload upload = new ServletFileUpload(factory);

        // 设置最大文件上传值
        upload.setFileSizeMax(MAX_FILE_SIZE);

        // 设置最大请求值 (包含文件和表单数据)
        upload.setSizeMax(MAX_REQUEST_SIZE);

        // 中文处理
        upload.setHeaderEncoding("UTF-8");

        // 构造临时路径来存储上传的文件
        // 这个路径相对当前应用的目录
        String uploadPath = req.getServletContext().getRealPath("./") + "/" + UPLOAD_DIRECTORY;
        System.out.println(uploadPath);

        // 如果目录不存在则创建
        File uploadDir = new File(uploadPath);
        if (!uploadDir.exists()) {
            uploadDir.mkdir();
        }

        try {
            // 解析请求的内容提取文件数据
//            Integer.parseInt("aa");
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(req);

            if (formItems != null && formItems.size() > 0) {
                // 迭代表单数据
                for (FileItem item : formItems) {
                    // 处理不在表单中的字段
//                    item.isFormField()判断是否为字符串
//                    new Random().nextInt()
                    if (!item.isFormField()) {
//                        取得文件名称
                        String fileName = new File(item.getName()).getName();
                        fileName = System.currentTimeMillis() + "--" + fileName;
//                        将文件保存到服务器的地址
                        String filePath = uploadPath + "/" + fileName;
                        File storeFile = new File(filePath);
                        // 在控制台输出文件的上传路径
                        System.out.println(filePath);
                        // 保存文件到硬盘
                        item.write(storeFile);
//                        需要将当前的文件保存到web里面去
                        String webPath = "E:\\wanxi\\step-4\\canyin04-0228\\web\\upload";
//                        File temp = new File(webPath);
//                        if (!temp.exists()) {
//                            temp.mkdir();
//                        }
                        File webSrc = new File(webPath, fileName);
                        copy(filePath, webPath, fileName);
//                        item.write(webSrc);//item只能用一次，用完就关闭了
                        return "/" + UPLOAD_DIRECTORY + "/" + fileName;
                    }
                }
            }
        } catch (Exception ex) {

        }
        return "";
    }

    /**
     * 将一个文件赋值到另一个文件
     *
     * @param oldPath
     * @param newPath
     */
    private static void copy(String oldPath, String newPath, String fileName) {
        File directory = new File(newPath);
        if (!directory.exists()) {
            directory.mkdirs();
        }

        try {
            InputStream inputStream = new FileInputStream(oldPath);
            int read = 0;
            OutputStream outputStream = new FileOutputStream(newPath + "/" + fileName);
            while ((read = inputStream.read()) != -1) {
//                System.out.println((char) read);
                outputStream.write(read);
            }
            inputStream.close();
            outputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


    }
}
